1. Field of the Invention
The present invention relates to video communication. More particularly, the present invention relates to a portable terminal capable of storing video and audio data relating to both sides of a video communication and a method for providing a video communication service using the same.
2. Description of the Related Art
Recently, portable terminals have been evolving to transmit data at a high speed, in addition to their basic function of voice communication. Particularly, a telecommunication network based on International Mobile Telecommunications-2000 (IMT-2000) standard may be used to implement high-speed data communication, as well as voice communication, via portable terminals. Data processed by portable terminals during data communication includes packet data and video data. When equipped with a camera or a television (TV) receiver, portable terminals can also process mobile image signals. Particularly, a telecommunication terminal equipped with a camera can take pictures of desired objects and display mobile or still images of the objects. In addition, the terminal can transmit the images to another terminal.
When a portable terminal incorporates a video communication function, the portable terminal transmits and receives video data, as well as audio data. For example, the portable terminal transmits a video image of its user and receives a video image of the other side (that is, the user's partner), so that the received data can be displayed during communication.
A conventional method for providing a video communication service by using a portable terminal, which incorporates a video communication function as mentioned above, uses a data service function and inserts control data into compressed audio and video data, which are then transmitted and received via a traffic channel. However, the conventional method has a problem in that delay or jitter, which results from channel characteristics, makes it impossible to guarantee reliable quality of speech (QoS). Therefore, the transmission side of the terminal uses a predetermined protocol in order to detect loss of data, which occurs during the transmission and reception processes, and implement real-time streaming.
Such loss of audio and video data mainly occurs during transmission via wireless environments. In order to overcome this problem, a protocol, such as RTP (Real-time Transport Protocol), H.324M, H.323 or SIP, is used so that control data for error checking is transmitted together with the audio and video data. The H.324M, among the protocols, coordinates video communication standards in conformity with International Telecommunication Union—Telecommunication Standardization Sector (ITU-T). The H.324M is used to transmit compressed audio and video data from transmission-side terminals based on Wideband Code Division Multiple Access (WCDMA) scheme.
When a portable terminal incorporates a recording function in addition to a video communication function, the portable terminal can store video and audio data, which are received from the partner's terminal during video communication, or which are to be transmitted to the partner's terminal.
However, the conventional portable terminal has a limitation in that, although it can store either video and audio data to be transmitted to the partner's terminal or received from the partner's terminal, the portable terminal cannot store video and audio data from both sides of a video communication.
Accordingly, there is a need for an improved portable terminal and method for providing a video communication service in a portable terminal that stores video and audio data for both sides of a video communication.